This study will investigate, in a randomized, three-arm study, the effects of two interventions that are high in phytoestrogens on various parameters related to estrogen metabolism and fibrinolysis. Approximately 120 women will be randomized to receive an American Heart Association (AHA) Step 1 diet, an AHA Step 2 diet + 10 g/day flax seed, or a macrobiotic dietary intervention. Blood and urine samples will be drawn at baseline, and at three, six, nine, and twelve months, to examine both short and long-term effects of these interventions. Outcomes include blood and urine levels of total estrogens and estradiol, and related metabolites; antigens to plasminogen activator inhibitor-1 (PAI-1) and tissue plasminogen activator (t-PA), fibrin D-dimer, and von Willebrand Factor; and endothelial function as measured by high-resolution ultrasound. Blood levels of antioxidant vitamins and retinoids will also be examined.